James ward packard



(No Model.)

'J. W. PACKARD.

MERCURY AIR PUMP.

Patented Apr. 16, 1889.

7b Md'Chanfc/IZ Pump Media/11417 Pam b WITNESSES:

ATTORNEY.

UNITED STATES P TENT OFFICE.

JAMES WARD PACKARD, on NEW YORK, N. Y.

MERCURY AIR-PUMP.

SPECIFICATION forming part of Letters latent No. 401,581, dated April16, 1889.

Application filed May 19, 1888. fierial No. 274,437. (No model.)

To all whom it may concern:

Be it known that I, J AMES WARD PACKARD, a citizen of the United States,residing at New York, in the county of New York and State of New York,have invented certain new and useful Improvements in Mercury Air-Pumps;and I do hereby declare the following to be a full, clear, and exactdescription of the invention, such as will enable others skilled in theart to which it appertains to make and use the same.

The object of my invention is the production of a combination of mercurytrap and valve for air-pumps which shall beabsolutely impervious to thepassage of air and at the same time be free from the liability tobreakage characteristic of the ordinary apparatus.

In the drawings, Figure 1 represents a wellknown form of mercury-pumpwith my invention attached. Fig. 2 is a vertical section showing on anenlarged scale my invention. Fig. 3 is a detail view of the siphon, theline of sight being in the direction of the arrow in Fig. 2.

In the drawings,P represents the mercurypump, well known in the art,having the vacuum-bulb G and the mercury-bulb G. The lamp L is attachedfor the purpose of exhausting the air from the bulb. The upper portionor neck of the pump is all made in one piece and sealed on to thevacuum-bulb G. \Vithin the chamber M, Fig. 2, is the siphon S, havingthe upright portion E and the inverted portion E. The space 0 within thechamber M is filled with mercury nearly to the level of the bend betweenthe portions E and E of the siphon. WVithin the chamber N, above thesiphon-chamber, is placed the floating glass valve V. Between thechamber N and the chamber M the neck of the pump is drawn in, so as toform a valve-seatflV, for the valve V.

The operation of the pump is in the wellknown way. The mechanicalair-pumps connected by means of the pieces of hose shown in Fig. 1 areoperated in such manner as to force the mercury from the bulb G into thevacuum-bulb G. As the mercury rises, it forces all the air above it upto the siphon S. The air bubbles up through the mercury in the space 0and escapes under the valve V. When the action of the mechanical pumpsis reversed, the mercury is withdrawn from the vacuum-bulb G, the valveV comes down upon its seat W, and the mercury in the chamber M preventsany small quantity of air which may slip under the valve V from passingon to the vacuum-bulb G". Thus a complete vacuum is left within the bulbG, and the moment the mercury sinks below the connection of the bulb Gwith the lamp L an equilibrium of pressure results, and a great quantityof the air remaining within the lamp bulb L is removed. A sufficientnumber of repetitions of this operation produces a nearly completevacuum in the lamp-bulb L.

I am aware that a siphon sealed with mercury in the manner I havedescribed, and for the purpose of forming an air-tight trap, is not newin the art; but in practice the use of this device alone has been foundinoperative, for the reason that the great pressure upon the mercury inthe trap would drive a little of it back through the siphon at eachoperation, and soon it would be entirely exhausted and the pump cease towork. On the other hand, the use of the valve made in the ordinary wayhas been attended with difficulties, in that it was liable to breakagewhen suddenly lifted by the upflowing mercury, and also in that nomatter how carefully it was ground and fitted to its seat there was moreor less leakage, which, of course, interfered with the highestefficiency of the pump.

By combining the siphon and the valve and in making the whole in onecontinuous piece with the vacuum-bulb G, I have attained in practice acomplete air-check, which is absolutely impervious to the passage of airand which works with its highest efficiency for an indefinite period oftime. The mercury-trap and the siphon furnish the features ofimperviousness,while the valve above them prevents the forcing of themercury through the siphon and the consequent disabling of the pump. Inaddition, there is little danger of the valve V being lifted soviolently as to break it, and the sealing of the neck of the pumpcontaining my invention directly onto the vacuum-bulb leaves no jointsfor leakage.

Having therefore described my invention chamber, the siphon chamberbelow said both in essence and detail, what I claim as valve-chamber,the siphon within the siphonnew, and desire to protect by LettersPatent, chamber, and the vacuum-bulb below the si- I 5 is phon, theValve-chamber, siphon-chamber, si-

5 1. In a mercury-pump, the combination of phon, and vacuum-bulb allmade in one piece,

the siphon-chamber, the siphon in said chamsubstantially as described.

ber sealed by a quantity of mercury, a valve- In testimony whereof Iaffix my signature in chamber above the siphon-chamber, and a presenceof two Witnesses. floating valve seated Within said valve-cham- JAMESWARD PACKARD. 1o ber, substantially as described. Witnesses:

2. In a mercury-pump, the combination, CHAS. II. SONN, with thevalve-chamber, a valve seated in said JNO. M. ROBERTSON.

